Field-magnet for electric motors and generators.



A. B. REIMBRS.

FIELD MAGNET FOB ELECTRIC MOTORS AND GENEBATOES.- APPLICATION FILED APILZB, 1906'. RENEWED D110. 10, 1910.

998,302, Patented July 18, 1911.

- Alf 13 INVENTOR CL. 8.68M

g g BY ATTORNEKL UNITED STATES PATENT OFFICE.

ALFRED EDMUND REIMERS,

OF KANSAS CITY, MISSOURI.

FIELD-MAGNET FOR ELECTRIC MOTORS AND GENERATORS.

Application filed April 28, 1906, Serial No. 314,260. Renewed December 10, 1910.

To all whom 'it may concern:

Be it known that I, ALFRED EDMUND Rnnunns, a citizen of the United States, and resident of Kansas City, county of Jackson, and State of Missouri, have invented certain new and useful Improvements in Field- Magnets for Electric Motors and Generators, of which the following is a specification, reference being had to the accompanying drawing, forming a part thereof, in which similar letters of reference indicate corresponding parts.

My invention relates to fieldmagnets for electric motors and generators; the objects of the invention being to provide means for preventing sparking at the commutator brushes and weakening and distortion of the magnetic field, further objects being to provide a structure of this character embodying a very compact and efiicient magnetic circuit, and to avoid cross connections in the series winding, whereby a considerable saving in copper is efiected.

The invention will be hereinafter fully described and specifically set forth in the annexed claims.

In the accompanying drawing forming part of this specification, Figure 1, is an end elevation of my improved field-magnet showing part of the main field winding in cross section, and also showing an armature; Fig. 2, a longitudinal sectional view taken on the line 2 2, of Fig. 1, and having the armature removed; and Fig. 3, is 21. diagrammatic view of my invention illustrating the winding.

In the practice of my invention I employ first, a method of applying the main field winding of a dynamo or motor, whether it be series, shunt or compound, in such a manner as to occupy a minimum of space, allow sutficient surface for proper ventilation, and, withal make the shortest possible magnetic circuit; second, a method of applying an auxiliary winding in series electrical connection with the armature, or in other words, through which all the current passing through the armature must pass in such a way as to completely counteract the cross-magnetizing force of the armature, thus preventing weakening and distortion of the magnetic field and sparking of the brushes under any overload or even reversal at full load.

In the example shown in the drawings, I have illustrated a four-pole field magnet.

Specification of Letters Patent.

Patented July 18, 1911.

Serial No. 596,716.

A is the metallic field frame and yoke which is preferably composed of cast steel, and which carries the magnet poles B; these are built up of thin sheet iron punchings, and, through the medium of the cast steel anchors C, (which hold the laminat-ions together) are bolted to the pole steps a, which are formed integral wit-h the frame A. When the poles are in position they form, together with the yoke and the pole tips 6, a channel D, which is completely filled with the main field winding E.

F, illustrates strips of insulating material to hold the main field winding in place. The field winding consists of four coils which are wound on formers. It can readily be seen that the magnetizing force of these coils acts directly on the yoke and magnet poles, and acts upon the armature through the medium of the pole tips, thus making a compact magnetic circuit of low reluctance. Then, finally, this improvement consists in placing the main field winding in channels formed by the conjunction of the pole tips, and of any desired shape or number, (of course the number is equal to the desired number of poles), which are parallel with the shaft of the machine.

The pole tips 5, are of sufficient thickness to admit of the grooves 1, 2, 3, 4, 5, 6, 7, 8, and 9, 10, 11, 12, 13, 14C, 15, 16, containing the series winding H. The series winding in the cylindrical groove 0, is simply to aid the winding in the grooves 1, 2, 3, etc.

The diagram (Fig. 3) shows an armature J, commutator K, and brushes L, and the connections of my improved series winding as applied to a four pole shunt dynamo. The arrows drawn on the wires show the direction of the current in all the windings when the armature is rotating in the direction shown by the arrow X. Only two of the poles are shown, as they are suflicient to illustrate the method of connecting.

The advantage in winding the series coils completely around the pole tips is evident.

by a comparison of the magnetizing power of the wires in the grooves 1, 2, 3, 4, 5, 6, 7, etc., and those in the grooves c. As the magnetizing power of a coil is proportional to its number of turns and the current passing through it, each wire in any of the grooves 1, 2, 3, 4L, 5, and 9, 10, 11, 12, 13, have double the magnetizing power of each wire in 0, since the former wire passes completely around the pole tip, forming one turn, whereas each wire in the slot 0, forms only a half turn since it passes in only one direction and along the pole face only. Thus it follows that coils wound on the pole tips in this manner require less space and shal lower grooves to create the same magnetic flux than if all the wires were wound in grooves 0. Moreover it concentrates this magnetic force where it is most needed, at the pole tips. For instance, the wires in the grooves 5, 6 or 13, 14, have in themselves half the magnetizing force that all those in the groove 0 have. And again, it saves copper in that it eliminates cross connections such as shown at I.

It is obvious that my invention is applicable to either electro-dynamie motors, or dynamo-electric generators.

I do not confine myself to the employment of grooves of the specific form or number shown in the drawings, as it is obvious that under the scope of my invention I am entitled to slight structural variations.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

I. A dynamo-electric machine having a field-magnet comprising a yoke and a plurality of poles formed by cores having arms extending in opposite directions, each of said arms having an inner and an outer set of grooves, and series-coils wound on said arms within the grooves thereof, and fieldcoils wound on said cores and lying over said arms, substantially as shown and described.

2. A dynamo-electric machine having a field-magnet comprising a plurality of poles embodying cores running parallel with the shaft of the motor, each core embodying a central part having a groove in its face, and oppositely extending arms having inner and outer grooves, said arms, in conjunction, forming channels, and series-coils wound around the arms of the cores and within the grooves thereof, and field-coils wound on the central parts of said cores and lying over the arms thereof and within the said channels, substantially as shown and described.

3. A fieldmagnet comprising .a yoke and a plurality of poles, each pole embodying a core having a central part, a face groove and arms extending therefrom in opposite directions, said arms having inner and outer grooves, and field-coils wound around the central parts of the said cores and lying over the arms thereof, and series-coils wound around the arms within the grooves thereof and the face grooves of the central parts of the cores, substantially as shown and described.

at. A dynamo-electric machine having a field-magnet comprising a yoke and a plurality of poles formed by cor-es having arms extending in opposite directions, each of said arms having an inner and an outer set of grooves, and series-coils wound on said arms within the grooves thereof, and fieldcoils wound on said cores and lying over said arms, substantially as shown and d e scribed.

5. A dynamo-electric machine having a field-magnet comprising a plurality of poles running parallel with the shaft of the motor, each pole embodying a central part, having a groove in its face, and oppositely extending arms having inner and outer grooves, said arms, in conjunction, ij'orming channels, and series-coils wound around the arms of the cores and within the grooves thereof, and field-coils wound on the central parts of said cores and lying over the arms thereof and within the said channels, substantially as shown and described.

6. A field-magnet comprising a yoke and a plurality of poles, each pole embodying a central part, having a face groove, and arms extending therefrom in opposite directions, said arms having inner and outer grooves, and field-coils wound around the central. parts of the said cores and lying over the arms thereof, and series-coils wound around the arms within the grooves thereof and the face grooves of the central parts of the cores, substantially as shown and described.

In testimony that, I claim the foregoing as my invention, I have signed my name in presence of two witnesses, this seventh day of April 1906.

ALFRED EDMUND REIMERS.

IVitnesses IV. E. CARY,

Jon 0. CAMPBELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

